This invention concerns a novel branched siloxane-silalkylene copolymer which contains one radical-polymerizable organic group per molecule, a silicone-containing organic polymer made by polymerizing the copolymer and a process for producing the same.
Organopolysiloxanes which contain one radical-polymerizable organic group per molecule, such as an acryloxy group or methacryloxy group are known, for example straight-chain dimethylpolysiloxanes of which only one end is blocked with methacryloxypropyl group, and branched methylpolysiloxanes represented by the formula: 
are known (see Japanese Patent Application Laid-open Nos. Hei 7-196975, Hei 1-319518 and Hei 1-254719). However, previous branched organpoolysiloxanes were limited to those having one branching point per molecule, and multiple branched organopolysiloxanes containing radical-polymerizable organic groups that have two or more branching points were not known.
Further, methods for improving the surface properties of organic polymers by copolymerizing a linear or branched organopolysiloxane containing 1 such radical-polymerizable organic group per molecule as a macro-monomer and a radical-polymerizable organic monomer are known (see Japanese Patent Application Laid-open Nos. Hei 7-196975, Hei 1-319518 and Hei 1-254719). However, there were problems with the silicone-containing organic polymers obtained in this way, in that compatibility with non-silicone-containing organic resins was low, and mechanical strength was low. Further, in order to obtain adequate surface-improvement properties by means of the silicone, it was necessary to copolymerize the aforesaid organopolysiloxane in comparatively large amounts and as a result the aforesaid problems became more pronounced.
Consequently, a purpose of the present invention is to provide a novel, muitiple branched siloxane-silalkylene copolymer which contains 1 radical-polymerizable organic group per molecule, and has a highly branched structure.
Further, a purpose of the present invention is to provide a silicone-containing organic polymer of high mechanical strength, good compatibility with organic resins, and having excellent surface-improvement properties, and a method for the production thereof.
Firstly, the branched siloxane-silalkylene copolymer of the present invention is explained.
The branched siloxane-silalkylene copolymer of the present invention is represented by the general formula: 
In the above formula, R1 is 1-10 carbon alkyl or aryl, with the alkyl group being exemplified by methyl, ethyl, propyl, butyl, pentyl, isopropyl, isobutyl, cyclopentyl and cyclohexyl, and the aryl group being exemplified by phenyl and naphthyl. Among these, methyl and phenyl are preferable, and methyl is especially preferable. X1 is a silyl-alkyl group represented by the following formula in the case when i=1. 
In the formula, R2 is 2-10 carbon alkylene, and is exemplified by straight-chain alkylene such as ethylene, propylene, butylene and hexylene and by branched alkylene such as methylmethylene, methylethylene, 1-methyl pentylene and 1,4-dimethylbutylene. Among these, ethylene, methylmethylene, methylethylene, hexylene, 1-methyl pentylene and 1,4-dimethylbutylene are preferable. R3 is 1-10 carbon alkyl, and is exemplified by methyl, ethyl, propyl, butyl, pentyl, isopropyl, isobutyl, cyclopentyl and cyclohexyl. Among these, methyl is preferable. R1 is the same as aforesaid. Xi+1 is a group selected from the group comprising a hydrogen atom, 1-10 carbon alkyl, aryl and the aforesaid silylalkyl group. ai is an integer from 0 to 3, and the mean total number of ai in 1 molecule is preferably 1.5ixc3x973 or less. i is an integer from 1 to 10, and this indicates the generation number of the said silylalkyl group, i.e. the number of repetitions of this silylalkyl group. Hence, if the generation number is 1, the branched siloxane-silalkylene copolymer of the present invention is represented by the general formula: 
(in the formula, Y is as defined below, R1, R2 and R3 are the same as aforesaid, and R9 is a hydrogen atom or the same as the aforesaid R1, and a1 is the same as the aforesaid ai), and if the generation number is 2, the branched siloxane-silalkylene copolymer of the present invention is represented by the general formula: 
(in the formula, Y is as defined below, R1, R2, R3 and R9 are the same as aforesaid, and a1 and a2 are the same as the aforesaid ai), and if the generation number is 3, the branched siloxane-silalkylene copolymer of the present invention is represented by the general formula: 
(in the formula, Y is as defined below, R1, R2, R3 and R9 are the same as aforesaid, and a1, a2 and a3 are the same as the aforesaid ai), Y is a radical-polymerizable organic group, and specifically, a (meth)-acryl group-containing organic group represented by the general formula: 
a styryl group-containing organic group represented by the general formula: 
or 2-10 carbon alkenyl are mentioned. In the above formulae, R4 and R6 are a hydrogen atom or methyl. R5 and R8 are 1-10 carbon alkylene, exemplified by straight-chain alkylene such as methylene, ethylene, propylene, butylene, and hexylene and by branched alkylene such as methylmethylene, methylethylene, 1-methyl pentylene, and 1,4-dimethylbutylene, R7 is 1-10 carbon alkyl, b is an integer from 0 to 4, and c is 0 or 1. As this radical-polymerizable group, for example acryloxymethyl, 3-acryloxypropyl, methacryloxymethyl, 3-methacryloxypropyl, 4-vinylphenyl, 3-vinylphenyl, 4-(2-propenyl)phenyl, 3-(2-propenyl)phenyl, 2-(4-vinyl -phenyl)ethyl, 2-(3-vinylphenyl)ethyl, vinyl, allyl, methallyl and 5-hexenyl are mentioned.
Such branched siloxane-silalkylene copolymers of the present invention are exemplified by the polymers represented by the following average molecular formulae: 
As a method for the production of such branched siloxane-silalkylene copolymers of the present invention, for example a method in which a silicon compound containing a silicon-bonded hydrogen atom represented by the general formula: 
(in the formula, R1 and Y are the same as aforesaid) and an alkenyl group-containing organo-silicon compound are subjected to a hydrosilylation reaction is mentioned. As the silicon compound represented by the above formula, for example, 3-methacryloxypropyltris-(dimethylsiloxy)silane, 3-acryloxypropyltris(dimethylsiloxy)silane, 4-vinylphenyltris-(dimethylsiloxy)-silane, 4-vinyltris(dimethylsiloxy)silane and 5-hexenyltris(dimethylsiloxy) -silane are used. As the alkenyl group-containing organosilicon compound, for example, vinyltris(trimethylsiloxy)silane, vinyltris(dimethylphenylsiloxy)silane and 5-hexenyltris -(trimethylsiloxy)silane are used. This hydrosilylation reaction is preferably performed in the presence of a transition metal catalyst such as chloroplatinic acid or a platinum-olefin complex. Further, as regards the compounding ratio of the two, in order to prevent the carbon-carbon double bonds in the silicon-bonded hydrogen atom-containing silicon compound represented by the above formula from undergoing the hydrosilylation reaction, it is preferable to use more than the stoichiometric amount of the alkylene group-containing organosilicon compound.
Further, the branched siloxane-silalkylene copolymer of the present invention can also be produced by a method in which a silicon-bonded alkoxy group-containing organosilicon compound and a tetraalkyldisiloxane compound are reacted in the presence of an acidic aqueous solution and the major part of the alkoxy groups in the reaction product obtained are replaced by dialkylsiloxy groups. Moreover, by subjecting an alkylene group-containing organosilicon compound to a hydrosilylation reaction, in the same way as aforesaid, with the resulting branched siloxane-silalkylene copolymer of the present invention, the number of repetitions of the silylalkyl groups can be increased. Further, the silicon-bonded alkoxy group-containing organosilicon compound used in this method can be produced by subjecting a silicon-bonded hydrogen atom-containing silicon compound represented by the general formula: 
(in the formula, R1 and Y are the same as aforesaid) and an alkylene group-containing alkoxy silane compound to a hydrosilylation reaction. The same compounds as aforesaid are used as the silicon-bonded hydrogen atom-containing silicon compounds and for example vinyl-trimethoxysilane, 5-hexenyltrimethoxysilane or vinyltriethoxysilane are used as the alkylene group-containing alkoxysilane compound.
Next, the silicone-containing organic polymer of the present invention is explained.
The silicone-containing organic polymer of the present invention is a polymer made by polymerizing (A) 0-99.9 weight parts of a radical-polymerizable organic monomer, and (B) 100-0.1 weight parts of a radical-polymerizable organic group-containing branched siloxane-silalkylene copolymer and represented by the general formula: 
(in the formula, Y, R1 and X1 are the same as aforesaid).
There is no particular limitation as to the radical-polymerizable organic monomer component (A) used in the production of this silicone-containing organic polymer, provided that it is a monomer which has a radical-polymerizable group. This radical-polymerizable group is preferably vinyl, vinylene or vinylidene. As such radical-polymerizable organic monomers, for example, unsaturated carboxylic acid ester compounds such as methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, n-octyl acrylate, glycidyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, octafluoropentyl acryl ate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate and octafluoropentyl methacrylate; unsaturated aliphatic carboxylic acid compounds such as methacrylic acid and acrylic acid; unsaturated carboxylic acid amide compounds such as acrylamide, methacrylamide and N-methylolacrylamide; unsaturated aliphatic nitrile compounds such as acrylonitrile and methacrylonitrile; unsaturated aliphatic compounds such as vinyl acetate, vinyl propionate and vinyl versatate; unsaturated carboxylic acid anhydrides such as maleic anhydride and 4-methacryloxy-trimellitic anhydride (4-META); halogenated vinyl compounds such as vinyl chloride and vinyl fluoride; aromatic vinyl compounds such as styrene, methylstyrene, vinyltoluene and vinylpyridine; and aliphatic diene compounds such as butadiene and isoprene are mentioned. These radical-polymerizable organic monomers such as the aforesaid can be used singly and, further, mixtures of 2 or m ore can also be used.
The component (B) essential in the production of the silicone-containing organic polymer of the present invention is a radical-polymerizable organic group-containing branched siloxane-silalkylene copolymer represented by the aforesaid general formula.
Concerning the ratio of the aforesaid component (A) and component (3) polymerized in the production of the silicone-containing organic polymer of the present invention, the weight ratio of component (A) to component (B) is in the range from 0:100 to 99.9:0. 1, and is preferably in the range from 1:99 to 99:1. Further, the statement that the first component is 0 weight parts means that a silicone-containing organic polymer of the present invention can be a homopolymer of component (B).
There is no particular limitation as to the polymerization method for the production of the silicone-containing organic polymer of the present invention, but usually a radical polymerization method or an ionic polymerization method is used. Of these, the radical polymerization method is preferably used, and in particular, the solution polymerization method is ideally used. Solution polymerization is generally performed by reacting 0-99.9 weight parts of component (A) and 100-0.1 weight parts of component (B), in a solvent, in the presence of a radical initiator, for 3-20 hours at 50 to 150xc2x0 C. Solvents used for this are exemplified by aliphatic hydrocarbons such as hexane, octane, decane and cyclohexane; aromatic hydro carbons such as benzene, toluene and xylene; ethers such as diethyl ether, dibutyl ether, tetrahydrofuran and dioxane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and diisobutyl ketone; and esters such as methyl acetate, ethyl acetate, butyl acetate and isobutyl acetate. Of these, toluene or xylene is ideally used. As the radical initiator, any previously known substance normally used in the radical polymerization method is used, and these are specifically exemplified by azobis compounds such as 2,2xe2x80x2-azobis(isobutyronitrile), 2,2xe2x80x2-azobis(2-methylbutyronitrile) and 2,2xe2x80x2-azobis(2,4-dimethylvaleronitrile); and organic peroxides such as benzoyl peroxide, lauroyl peroxide, tert-butyl peroxybenzoate and tert-butyl peroxy-2-ethylhexanoate. One of these radical initiators can be used alone; further, a mixture of two or more may be used. The quantity of radical initiator used is preferably in the range 0.1 to 5 weight parts per 100 total weight parts of the aforesaid component (A) and component (B). Further, chain transfer agents can be also added when the silicone-containing organic polymer of the present invention is produced. As such chain extenders, specifically, mercapto compounds such as 2-mercaptoethanol, butyl mercaptan, n-dodecyl mercaptan and 3-mercaptopropyltrimethoxysilane; and halogenated compounds such as methylene chloride, chloroform, carbon tetrachloride, butyl bromide and 3-chloropropyltrimethoxysilane are mentioned.